From: Dave Martin <Dave.Martin@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
gdb@sourceware.org, "Alan Hayward" <alan.hayward@arm.com>,
"Will Deacon" <will.deacon@arm.com>,
"Zhang Lei" <zhang.lei@jp.fujitsu.com>,
"Julien Grall" <julien.grall@arm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Alex Bennée" <alex.bennee@linaro.org>
Subject: [PATCH v2 0/3] arm64/sve: Fix mutating register endianness on big-endian
Date: Wed, 12 Jun 2019 17:00:31 +0100 [thread overview]
Message-ID: <1560355234-25516-1-git-send-email-Dave.Martin@arm.com> (raw)
This is a respin of [1], swapping the first two patches so that (new)
patch 1 can go to stable stand-alone without depending on patch 2.
I've also smuggled in a new trivial patch 3, that just replaces a
couple of magic numbers for which there is now a suitable #define to
use, which have been bugging me for a while.
Original blurb:
By inspection while debugging something else, I noticed that the byte
order of FPSIMD V-register stores and SVE Z-register stores is not the
same when running on big-endian.
This is not properly taken into account when moving between the FPSIMD
and SVE register views inside the kernel, resulting in the bytes of a
V-register getting spontaneously reversed in some situations, from
userspace's point of view. The signal frame and ptrace interface are
also affected. The KVM ABI forbids mixing the two views and so should
not be affected.
See patch 2 for details.
Patch 1 does some trivial preparatory refactoring.
gdb may or may not be affected by this, depending on how it uses the
NT_PRFPREG and NT_ARM_SVE regsets. I'll leave it to the developers to
assess that.
[1] [PATCH 0/2] arm64/sve: Fix mutating register endianness on big-endian
http://lists.infradead.org/pipermail/linux-arm-kernel/2019-June/657824.html
Dave Martin (3):
arm64/sve: Fix missing SVE/FPSIMD endianness conversions
arm64/sve: Factor out FPSIMD to SVE state conversion
arm64/sve: Fix a couple of magic numbers for the Z-reg count
Documentation/arm64/sve.txt | 16 +++++++++++
arch/arm64/include/uapi/asm/kvm.h | 7 +++++
arch/arm64/include/uapi/asm/ptrace.h | 4 +++
arch/arm64/include/uapi/asm/sigcontext.h | 14 +++++++++
arch/arm64/kernel/fpsimd.c | 49 ++++++++++++++++++++++++--------
5 files changed, 78 insertions(+), 12 deletions(-)
--
2.1.4
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next reply other threads:[~2019-06-12 16:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 16:00 Dave Martin [this message]
2019-06-12 16:00 ` [PATCH v2 1/3] arm64/sve: Fix missing SVE/FPSIMD endianness conversions Dave Martin
2019-06-12 17:28 ` Will Deacon
2019-06-27 13:51 ` Catalin Marinas
2019-06-27 15:18 ` Dave Martin
2019-06-12 17:46 ` Julien Grall
2019-06-13 9:22 ` Will Deacon
2019-06-13 10:00 ` Dave Martin
2019-06-13 10:17 ` Will Deacon
2019-06-13 10:20 ` Dave Martin
2019-06-12 16:00 ` [PATCH v2 2/3] arm64/sve: Factor out FPSIMD to SVE state conversion Dave Martin
2019-06-20 13:45 ` Julien Grall
2019-07-22 10:31 ` Catalin Marinas
2019-06-12 16:00 ` [PATCH v2 3/3] arm64/sve: Fix a couple of magic numbers for the Z-reg count Dave Martin
2019-06-20 13:43 ` Julien Grall
2019-07-22 10:32 ` Catalin Marinas
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